Ordinary dropside playpens have been severely criticized since they enable babies to climb or roll over the edge of the platform floor where the side is dropped and the netting is loose. That problem was solved by an arrangement which does not allow the sides to drop until the floor is folded vertical. See U.S. Pat. Nos. 3,474,472 and 3,206,773.
The prior art still has the problem of permitting one side to fold in instead of out before the operator realizes what is happening. Thus, it is possible to strain or bend some of the links.
The problem is solved by providing a positive means which causes the pivoting portions to pivot outwardly in opposite directions at the same time and through the same distance relative to a common bracket.